About the Cover: the Riemann Zeta Function A Tribute to Bernhard Riemann's 200th Birthday

Honoring the 200th birthday of Bernhard Riemann on September 17, the cover of this volume shows a phase plot of the Riemann Zeta Function. In this essay we present some features of this function in an entertaining way. Using only basic tools, we try to make it clear that Zeta is, on the one hand, very "simple" and, on the other hand, incredibly complex. In particular, we give an interpretation of its universality and illustrate this property by phase plots. The last section is devoted to philosophical speculations on the Riemann Hypothesis.